Care for people suffering from a dementing illness is complicated, stressful, and often expensive. Of the various problems faced by family caregivers, disturbances in behavior and mood are the most stressful and often lead to the breakdown of the caregiving situation and institutionalization of the patient. One of the more promising ways of addressing care needs for patients living in the community is through adult day service programs (ADS), which provide structured activities that utilize patients' remaining abilities and give caregivers a break from the often continuous pressures they face. In previous work by our research group, we found that caregivers who enrolled a relative with dementia into an ADS program experienced significant reductions in care- related stressors and improved well-being, compared to a control group. The proposed study extends that work by exploring the effects of ADS on the behavior and mood of dementia patients. ADS may affect behavior and mood by keeping patients involved in structured activities. By easing the problems faced by family caregivers, ADS use may also reduce use of health and long term care services. The proposed study will use a quasi-experimental, nonequivalent group design. People with dementia who are starting an ADS program and their caregivers will be compared to a control group not using these services. It is hypothesized that dementia patients using ADS will experience significant reductions in behavior problems and depressive symptoms over time, compared to controls. We also expect that caregivers in the ADS group will experience decreases in care-related stress and improved well-being, and will use fewer health and long-term care services than the control group. These changes will be mediated by improvements in their relative's behavior.